State of the art in Graphics Toolkits

First of all, yes, I have searched the forums. However, I was hoping to get a feel for the current state-of-the-art in graphics toolkits that use openGL. I know this forum is really for OpenGL programming questions but I think some of the Graphics gurus on this page are ideally suited to answer this type of question.

I’m curious about toolkits that are suited for cad/fem (finite element modeling) applications. Something similar to HOOPS or OpenCascade. I really like the look of HOOPS but it’s $$$$. OpenCascade screenshots look nice but it is HUGE. So, I’m looking for alternatives before I dump $$$$ into HOOPS. Any and all comments related to OpenGL graphics toolkits would be much appreciated. Thanks in advance.